title: Re-examination of resistance of Toxoplasma gondii tachyzoites and bradyzoites to pepsin and trypsin digestion.
abstract: The effect of digestion in trypsin and acid pepsin on Toxoplasma gondii tachyzoites and bradyzoites was re-evaluated because of recent use of this method to distinguish tachyzoites from bradyzoites. Toxoplasma gondii tachyzoites survived better in 0.5% trypsin solution for 1 h than in 1.0% solution, and occasionally survived for 2 h in acid pepsin solution. Extracellular tachyzoites (> or = 1000) were also infectious orally to mice and cats. Bradyzoites survived equally in trypsin and acid pepsin solutions but the digestion of brain tissue in 0.5% trypsin solution was better than in acid pepsin solution. The resistance to digestion in acid pepsin solution is not a reliable method to distinguish tachyzoites from bradyzoites.
authors.affiliation: United States Department of Agriculture, Parasite Biology and Epidemiology Laboratory, Beltsville, Maryland 20705-2350, USA. JDUBEY@GGPL.ARSUSDA.GOV
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000469:parasitology; D001921:Brain / Q000469:parasitology; D002415:Cats; D006790:Host-Parasite Interactions; D008018:Life Cycle Stages; D008168:Lung / Q000469:parasitology; D051379:Mice; D010434:Pepsin A / Q000378:metabolism / Q000494:pharmacology*; D013045:Species Specificity; D014122:Toxoplasma / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity; D014124:Toxoplasmosis, Animal / Q000469:parasitology*; D014357:Trypsin / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D014357:Trypsin; D010434:Pepsin A